bradford



No. l625,368.

Patented May 30, |899. n. E. BRADFQRD. 1 CUMPOUND ENGINE.

(Application led May 14, 1897.)

(No Model.)

2 Sheets-Sheet I..

No. 625,868. Patented May 30, i899..

. B. E. BRADFORD.

COMPOUND ENGINE.

(Appieaninn med may 14, 1897.)

(No Modal.) A 2 shees-sheet2- UNITED STATES PATENT OFFICE RIOHAEDE. BRADFORD, OF LONDON, ENGLAND.

cot/,liaouluo ENGlNFE.

SPECIFICATION forming par@ @framers Patent No. 625,868, dated May 3o, 1899. Applicationliled May 14.1897.'V Serial No. 636,453. (No model.)

To all whom it may concern,.-

Be it known that I, RICHARD ERNEST BRAD- FORD, asubj ect of the Queen of Great Britain, residing at London, England, have invented certain new and useful Improvements in Compounding Fluid-Pressure `l\Iotive-Power Engines, (which was patented in Germany under date of May 12,1897, No. 97,908,) of which the following is a full, clear, and exact `descripl tion. Y

My invention relates to an improved form of. engine in which the steam is allowed to expand to the full capacity of both the cylinders employed. The practical result is an increased capacity for work with an increased economy in the steam used.

I willpdescribe my invention by the aid of the accompanying drawings, in which Figure 1 is a verticalsection of a two-cylinder compounding-engine with the pistons arranged tandem and'all the parts shown in one plane for the sake of clearness. Y Fig. 2 is a horizontal section, leaving out the mov-1` ing parts; Fig. 3, a transverse section through ports b and o, as shown by the dotted line 3 3, Fig. l; Fig. 4,.a transverse section through port Ct, as shown by the dotted line 4 4, Fig. 1; Fig. 5, a transverse section through port cl d on line 5 5, Fig. 1. Figs. 3, 4, and 5 are various sections of one casting; Fig. 6, a transverse section through guide and other parts on line 6 6 of Fig. 2; Fig. 7, a transverse section through main bearngon line 7 7, Fig. 2. Fig. 8 shows the valve-gear. Figs. 9, 10, and 11 are diagrams representing various positions of the valves. Y

The drawings show the invention applied to an engine with pistons tandem and each cylinder single-acting.

The engine consists, essentially, of three castings. The first contains the low-pressure cylinder C' and spherical end C2, having an opening C3 communicating by means of the pipe cl' with the atmosphere or exhaust. `This casting is provided with a flange O4, by which it is connected to the second or middle casting.

The second ormiddle casting contains the highpressure cylinder B', the two valvechambers H and H', and the hollow foot I, containing the exhaust-passage d. The valvechambers H and H' are open `at their ends to the low-pressure cylinder C. The stuffingbox K, through which the rod K', connecting the pistons B and C, passes, isscrewed into the rear of the vhigh-pressure cylinder B', and the piston C is bell-shaped to enable it to pass over` the said stuiing-box K, and thus move throughout the entire length of the low-pressurecylinder C'.

The third or end casting forms the guide L for the cross-head K2. This casting has a curved arm L', connecting the guide L with the plumber-block L2, supporting the main bearing, in which is mounted the shaft M,

' having a disk M' and'crank-pin M2. The disk M' is formed with an eccentric M3, upon which Works the eccentric-strap 71.2.

In Figs. 9, l0, and llI have merely show a crank (marked Alinstead of a disk M' and crank-pin M2, and the eccentric has been indicated by means of a center A'.

Fig. l and the accompanying valve diagrams, Figs. 9, 10, and l1, show an 'engine whose parts are moving in the direction indicated by therespective arrows. The cycle commences with diagram Fig. 9. The crank A is on the top or back end, and steam admission is opening to work side of high-pressure pistonB, and the other side of high-pressure piston B and the work side of low-pressure piston C are opening to exhaust d, the other side of lowpressur.e piston C being always open to atmosphere or condenser through the pipes d' d2.

In Fig. 1 the engine is at `halt-stroke, the steam-admission port b is just closed, and all d. The low-presso re piston C is thus in equil- Zz'bfrz'o.

In diagram Fig. 10 the engine is at full stroke. The 'port bis now open to act as an intermediate passage, theintermediate port c being in the actof opening.` `The port e always remains open. There is thus communication between bothsides of the highpressure piston B and the crank side of the low-pressure piston C. The high-pressure piston B is thus n equilibrio. y

In diagram Fig. ll the engine is shown halfstroke back. The port b has closed. The intermediate port c is, however, open to its full extent.`

Between the position of the parts'indicated the rest of the engine isffull open to exhaust ICO in Figs. l1 and 9 the valves are moving in the direction indicated by the arrows in these figures, and rst the intermediate passage c is closed for cushioning the returning highpressure piston B. Then the steam is admitted to the high pressure cylinder B' through the cavity 71,8 of the valve h, and simultaneously the end h" of the valveh6 opens communication between the Work side of the low-pressure cylinder C and the exhaust d. In Fig. 9 the crank Ais shown about to commence a new stroke and the-valve h7 is about to open communication between the work side of the 10W-pressure cylinder C and the exhaust d. It is thus obvious, lirst, that both pistons are in equilibrio respectively g during their return stroke; second, all back pressure is avoided 5 third, the steam expands to the capacity of the high-pressure cylinder plus the 'capacity of the low-pressure cylinder; fourth, the steam being cut off at halfstrolie of high-pressure piston and-the cylinder being as one to four the expansion equals ten.

The details of this engine will be readily understood by reference to Fig. l.. The sections, Figs. 3, 4, and 5, show the actual shape and position of some of the parts of the central casting, these having been all represented in one plane at Fig. l, as before stated.

There aretwo arms h h onv the eccentricstrap h2, each of which is connected toa valverod, one of the valve-rods h3 having a guide h4. The other valve-rod h5 derives a parallel motion and a later period of action. The first Valve h thus facilitates a rapid opening for admission to both cylinders B C' and the second Valve 7L7 a sudden closing for cushioning to both cylinders B C', .thus doing the work of the ordinary expansion-gear combination.

In applying my invention to single-acting compound engines having one crank, as above described, the high and low pressure pistons are connected together onthe same pistonrod, and in applying my invention to singleacting compound engines having two cranks opposite to one another the high-pressure valve arrangement is the same as hereinbefore described.

What I claim is- 1. In a compounding fluid-pressure motivepower engine having a high and a low pressure cylinder, each cylinder having a piston connected to a single-crank shaft by means of a piston-rod and connecting-rod, the combination of an eccentric mounted on the crankshaft, said eccentric having two arms, the one actuating the valve for admitting steam to the high-pressure cylinder, cutting oif the steam, opening communication between the high-pressure cylinder and the low-pressure cylinder, and finally opening communication between the low-pressure cylinder and the exhaust, the other valve lirst opening communication between the work side of the highv pressure piston and the other side of the same,

and at the same. moment opening communication between the work side of the highpressure piston and the Work side of the lowengine, the combination of a high-pressure cylinder and a low-pressure cylinder, each having apiston mounted on the same pistonrod, and a pair of valves operated by rodsv connected to two arms of an eccentric mounted on the crank-shaft, one of said valves communicating with the source of fluid-pressure, then opening communication between the cylinders, and finally with the exhaust, the other valve placing the hi gli-pressure piston in equilibrio and opening communication with the low-pressure cylinder, and finally with the exhaust, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses. I

RICHD. E. BRADFORD.

Witnesses: l

B. J. B. MILLS, CLAUDE K. MILLS. 

